Thermostat



1.1 is a front perspective view;

1.2 is a bottom plan view;

1.3 is a top plan view;

1.4 is a left side elevation view;

1.5 is a right side elevation view;

1.6 is a front view; and

1.7 is a rear view.

The broken lines depict portions of the thermostat that form no part of the claimed design. 

CLAIM The ornamental design for a thermostat, as shown and described. 